Series lamp circuit with normal and stand-by lamps



H. J. STIER Oct. 8, 1957 SERIES LAMP CIRCUIT WITH NORMAL AND STAND-BY LAMPS Filed March 21, 1956 A m I u M (/0,

INVENTOR. BY flowurc/JSZ'ier h7T0/FN5X United States Patent SERIES LA'MP CIRCUIT WITH NORMAL AND STAND-BY LAlWPS Howard J. Stier, North Syracuse, N. Y., assignor to Grouse-Hinds Company, Syracuse, N. Y., a corporation of New York Application March 21, 1956, Serial No. 572,874

1 Claim. (Cl. 31590) This invention relates to a series lamp circuit. In many installations, such as street lighting, airport runway lighting, etc., it is economical to operate the lamps in a series circuit. In order to prevent an open circuit in the event one of the lamps burn out, a device known as a film cut-out is connected in shunt with each lamp in the series circuit. In the event a lamp burns out, the voltage in the circuit will rise to a value which will puncture the film cut-out, re-establishing the circuit, and there is means included in the feed supply for the circuit to automatically adjust the circuit voltage to compensate for the loss of the burned-out lamp.

In some installations, it is important that the circuit is not operated with a burned-out lamp as, for example, in certain signal circuits and in circuits used for runway lighting at airports. Many types of lamp changing apparatus have been developed and which function to automatically connect a new lamp in the circuit to replace a burned-out lamp. However, these automatic lamp changers are expensive to construct and maintain, and are not practical for use on a series circuit.

This invention has as an object a series lamp circuit including a number of lamps normally connected in the circuit and in addition, a stand-by lamp for each of the normal lamps, and a simple and inexpensive arrangement Patented Oct. 8, 1957 for substituting a stand-by lamp in the event its associated normal lamp burns out.

The invention consists in the novel features and in the combinations and constructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanying drawing which is a diagrammatic illustration of a series lamp circuit embodying my invention.

10 designates one end or side of a series lamp circuit, the other side of which is indicated at 10. This circuit includes a number of lamps 11, there being three shown in the drawing, connected in series in the circuit.

There is also provided a stand-by lamp 12 corresponding to each of the normal lamps 11, the lamps 12 being connected in shunt with the lamps 11, and a film cut-out 13 is connected in series with the lamp 12 through wires 14, 15, 16, 17 and 18.

With this arrangement, when any one of the lamps 11 burns out, the film cut-out 13 becomes punctured, bringing the associated lamp 12 into the series circuit and thus maintaining the same number of lights burning in the circuit. Inasmuch as the arrangement is a series lamp circuit, a second film cut-out 19 is connected in shunt with each of the lamps 12 through wires 20, 21, 22, and 23, to re-establish the circuit in the event a stand-by lamp :also burns out.

It will be apparent that my series circuit arrangement provides for the automatic substitution of a stand-by lamp in the event its associated main or normal lamp burns out, and that the only apparatus employed to efiect this arrangement consists of the film cut-outs 13 and 19.

What I claim is:

A series lamp circuit, a first lamp connected in series in said circuit, a second lamp connected in shunt with said first lamp, a filament cut-out connected in series with said second lamp, and a second film cut-out connected in shunt with said second lamp.

No references cited. 

